As of later this year, probably October, the population of the United States is expected to hit 300 million people. As a tribute to this event, InfoPlease has put together a list that compares all kinds of statistics from today with those of when the U.S. hit 100 million and 200 million in population.

For example,

Price of a new home
2006: $290,600
1967: $24,600 ($149,147 in 2006 dollars)
1915: $3,200 ($64,158 in 2006 dollars)

Price of milk
2006: $3.00 gallon
1967: $1.03 gallon ($6.24 in 2006 dollars)
1915: $ .36 gallon ($7.22 in 2006 dollars)

Median Age of the Population
2006: 36.2
1967: 29.5
1915: 24.1

Safer on our Roads
2006: 42,643 - Number of traffic fatalities in 2003. This amounted to 1.5 fatalities per every 100 million vehicle miles traveled.
1967: 51,559 - Number of traffic fatalities. This amounted to 5 fatalities for every 100 million vehicle miles of travel.
1915: 6,779 - Number of traffic fatalities. This amounted to 35 fatalities for every 100 million vehicle miles of travel.

Visit their page for lots more: http://www.infoplease.com/spot/300-million-americans.html